Nov. 18,
2012: A 20" f/3.0 and a 30" f/3.0 are bornIt
was an uncharacteristically nice week in November when two fast
telescopes recently came into the world - one, a visual
instrument, the other, purely for imaging. Amazingly, both made
their debut during a string of clear nights in a month that can be notoriously
cloudy here in central Illinois, somehow avoiding the "new telescope curse" or multiple weeks of cloudy weather.

First, let's start with an absolutely amazing 20" f/3.0 instrument, seen at right, custom-built by John Pratte of JPAstrocraft.

The mirror comes is from the same batch of 1.25"-thick Pyrex blanks
that the mirror for my own 20" f/3 Starmaster came from. I also
figured the 5.0" m.a. flat elliptical secondary mirror.

The rest, as you see it here, was pure John Pratte. He created a
superb mirror cell with excellent edge support (which we tested in my
shop with the nearly-spherical mirror), a fantastically stiff
structure, beautiful woodwork, and numerous custom features.

You see, this is not a normal visual telescpe. It is configurable for monocular viewing with a SIPS (Starlight Integrated Paracorr System),
for binoviewing, and for using a Mallincam for "video astronomy".
Each application utilizes a different set of adapters to which
the upper cage and truss
poles attach. This avoids any compromise in the structural
integrity of the telescope.

I'm sure we'll hear more about this telescope after the finishing touches are done.

This telescope and tracking mount originally came to Bob as a 30" R-C telescope in need of work.

After it was picked up in New Mexico, the telescope drive electronics
were not really usable, but the mechanical parts and optics were
in working order.

New motors and a new drive system were procured and installed, and of
course an observatory was built to house the new instrument.

First light with the Cassegrain telescope showed images, but they were
fairly disappointing. Stars were not as sharp as those imaged
with Bob's 24" and 32" instruments.

After considerable frustration, Bob decided to convert the telescope to
a prime-focus Newtonian. In order to fit in the observatory, it
would need to be f/3.0, and the telescope would need to be moved north
within the building. Bob took care of this by pouring new
concrete piers to support the base of the telescope.

I was contracted to make the mirror, which was completed in
November of 2012. It was coated within a week, and by the next
week it was in the telescope!

Bob certainly doesn't mess around
when it comes to building instruments and getting them running.

It appears that the instrument is already a success - in its first few
days of operation its wide field and excellent image quality allowed it
to recover several "lost" NEOs, or NEOs that were not where they were
expected to be based on a calculated orbit that was a bit off of the
true orbit. So, this is truly an instrument that fills a niche
for Bob and his collaborators.

Below, the 30" f/3.0 is pictured as the sun sets before another night of data gathering.

Finally, we step inside the building that is right next to the
observatory housing the 30", and we see a true monster. This is
the massive fork mount that will soon support the 50" f/4 instrument. For those who speak metric, that's 1.3 meters.

I'll end this installment with this photo, and no
doubt you'll hear more about it in the future. Stay tuned.....